[Ocfs2-users] Significant Slowdown when writing and deleting files at the same time

[Peter Grandi]

> I have a 2 node test system sharing a 2TB volume with a
> journal size of 256MB.

> I can easily trigger the slowdown by starting to processes to
> write a 10GB file each, then I delete a different large file
> (7GB+) while the other processes are writing.  The slowdown is
> significant and very disruptive.

> Not only did it take over 3 minutes to delete the file, every
> else with pause when entering that directory too. [ ... ]

Thanks for confirming that the performance of OCFS2 is quite
good even under such demanding conditions.

Data structures with mandatory internal locking with high
latency are very difficult to parallelize, and OCFS2 as you
report does a pretty good job of that despite the contention of
three metadata intensive activities.

[ ... ]

> I would like any ideas that would provide smoother performance

The performance is pretty good and smooth, as both the speed and
latencies are about as good as it can get under such conditions.

> of the OCFS2 volume and somehow eliminate the long pauses
> during deletes.

Fund a large research programme to figure out whether it is
feasible to have large overlapping transactions without
interference in a filesystem with mandatory internal locking
with fairly high latency.